Silicone-containing copolymers are a class of polymeric materials that have found a wide variety of uses, including uses such as coatings (including release coatings), adhesives (including pressure sensitive adhesives), gaskets, tubing, vibration dampening materials and the like.
Many of these silicone-containing copolymers are polydiorganosiloxane-based copolymers. The unique properties of these copolymers are derived mainly from the physical and chemical characteristics of the siloxane bond and the organic substituents. Typically the outstanding properties of polydiorganosiloxane copolymers include resistance to ultraviolet light, extremely low glass transition temperature, good thermal and oxidative stability, high permeability to many gases, very low surface energy, low index of refraction, good hydrophobicity and good dielectric properties.
Traditionally silicone-containing copolymers have been prepared in solution. The dissolved copolymer is then cast or coated and dried. The solvents aid in the polymerization by solubilizing the reactants and also serve to dissipate the heat generated during exothermic reactions.
For a number of reasons, it may be desirable to form polymers without utilizing solvents or where the use of solvent is minimized. Environmental concerns, such as the release of solvents into the atmosphere and the need to recycle and/or dispose of the solvents after use, are prompting efforts to reduce or eliminate solvent use. Shipment of polymers dissolved in solvent can be difficult and expensive. Also, many common solvents are flammable requiring handling of polymer solutions with added safety precautions.